The Newest Hormone - Leptin

The Newest Hormone—Leptin
Following discovery of the ob gene in
1994, which codes for this newest hormone,
J. Friedman and coworkers
soon coined the term, leptin (Gr. leptos, thin), for the circulating hormone,
produced by white fat cells (adipose
tissue). Subsequently, receptors for
leptin have been found in many tissues,
but the primary site of action of
leptin appears to be the brain, particularly
the hypothalamus. Leptin is an
important hormone that regulates eating
behavior and energy balance as
part of a feedback system that informs
the brain as to the energy status of
the periphery. Leptin has become
immensely significant in the study of
sateity signals and energy expenditure,
since these studies relate to the overall
problem of human obesity. It
is of interest that blood plasma levels
of leptin mirror those of insulin, which
also provides an important feedback
signal to the brain.